Posted
by
timothy
on Sunday January 30, 2011 @01:17PM
from the no-this-is-me-in-a-nutshell dept.

An anonymous reader writes "In a feat of modern-day alchemy, atom tinkerers have fooled hydrogen atoms into accepting a helium atom as one of their own, reports New Scientist. Donald Fleming of the University of British Columbia in Vancouver, Canada, and colleagues managed to disguise a helium atom as a hydrogen atom by replacing one of its orbiting electrons with a muon, which is far heavier than an electron. The camouflaged atom behaves chemically like hydrogen, but has four times the mass of normal hydrogen, allowing predictions for how atomic mass affects reaction rates to be put to the test."

As I recall, the poor muon has an average lifetime of something like 2 microseconds. We might see some interesting theoretical chemistry come out of this (the reaction-rate question) but it looks like we'll end up a little light on practical applications of muons in chemical compounds.

I remember that much past interest over muons and hydrogen has been around muon-catalyzed fusion. As you say, the muons are quite short-lived, which prevents them from catalyzing enough H-H fusions to get to breakeven. And then there was the alpha-sticking problem, whereby helium nuclei products then grab the muons, thus stealing them away from the process.

Check out ultra-dense deuterium, though. It's some kind of exotic form of matter, and there have recently been some tantalizing glimpses of it in nano-sized clumps.

Yeah, like this. Sorry I didn't see your post. My Ph.D. advisor, Larry Biedenharn, was heavily involved in this for four or five years, but as I said, it didn't quite pan out partly because of the sticking problem, partly because one can only make muons at something like 10% energy efficiency (remembering from the many seminars we had on this back in those days, not looking up the exact numbers). Larry always thought they'd do it with a special "breeder" fission reactor to get the muons for free as a side-effect of making energy the other way to boost fission returns by a factor of 50% or so, but this never happened AFAIK.

It is still an open problem -- the question is really is there an environment where the He sticking problem is suppressed (they didn't find one, but I doubt the search was exhaustive) and is there any way to produce muons at higher efficiencies -- say some sort of resonant conversion of electrons into muons that beats 5-10%. My recollection is that they were within a factor of ten, maybe even within a factor of 2-3 of break even but couldn't quite find a way over the hump. They know way more about neutrinos now than they did back then -- one wonders if anybody is even thinking about it any more.

I think about it a different way: the way muons catalyse fusion reactions is by dramatically reducing the covalent bond length (due to their much greater mass, they orbit much closer to the nucleus). Ultra-short laser pulses are known to be able to "dress" electrons with effectively greater mass. I can't help but wonder if there's any prospects for using this to achieve the same thing.

The interesting possibility is and remains muon-catalyzed fusion. The stoichiometry is within roughly one order of magnitude of breaking even -- it costs too much to make a muon, a muon can catalyze too few fusion reactions to pay for itself in its lifetime, but it is close. Of course if you have a source of "free" muons, e.g. a nuclear reactor, one can basically use them to augment the energy production of the fission processes.

I thought that the auger replacement of electrons in diatomic hydrogen (a

I'm pretty sure nuclear weapons (you know, dealing with the nucleus of the atom) already are much more energetic than anything that merely chemical can hope to muster, whether it be electrons or muons in your atoms' orbitals.

(Also, muons generally decay in a couple of microseconds, which has the potential to complicate the weapon delivery system).

This doesn't necessarily exclude nuclear weapons. One of the ideas for fusion is to use hydrogen atoms with a muon instead of an electron orbiting them. Because the muon is heavier, it orbits closer, meaning that less energy is required to collide two together (once you get inside the lepton shell, the two nuclei repel each other until the strong attraction becomes greater than the electrostatic repulsion, at which point you have fusion).

Especially as you would be going 15444 times faster than the speed of light. The kinetic energy of 1kg of mass traveling at that speed (leaving aside that it is impossible) is equivalent to 2.5billion megatons of TNT so no need for any explosive component.

the change is in how it reacts chemically, so it would be unlikely to have nuclear effects, i suppose with enough you could try oxidizing it, but hydrogen gas doesn't make a good bomb, so this would likely not either.

You may be able to, but why would you want to. Helium is a lot more expensive than hydrogen to begin with, and this "mutated" helium is probably an order of magnitude more expensive still. Of course, hydrogen bombs work by fusing hydrogen into helium, so your bomb would have to fuse helium into lithium or beryllium. That's probably a harder reaction to establish and may not yield as much. (Although it should be noted that fusion bombs typically bombard lithium with neutrons and fission it into tritium,

This is super cool, but less for the kinetic isotope effect (KIE) studies and more for the muon-electron substitution. We've compared isotope masses with reaction rates using deuterium and tritium before, so using "H-4" and "H-5" is nice for extended validation, but not unexpected. The muonium is pretty bad-ass, though.

"It's possible we could fabricate power transmission lines directly from Transparent Muominium(TM) (TM), and disconnect the generating stations completely," declared a GE scientist, thumbing his nose at a rival division. "We've already begun a series of avian studies on TM power line s

It's an experiment confirming QM predictions of reaction rates varying with mass, not a way to produce a hydrogen alternative for general use (because a fast decaying hydrogen that you need a particle accelerator to make is so useful...)

Nah, it won't be useful outside of the lab. Those muons just decay too fast. This is very obnoxious, because muons catalyze fusion - they tighten up the nucleous, so it's easier for another atom to get in and fuse. If they lasted a bit longer (say 2x or 3x), then muon catalyzed fusion would be a practical energy source.

I will. At that small a quantity though, there's going to be a considerable per unit cost. 1 barrel of Helium, from Jupiter, guaranteed delivery, will cost you $49 billion. I'll bring you the contract tomorrow, if you're interested.

To be more specific, the molecular weight of normal He to He with one muon attached is roughly 4.1/4.0. The change in pitch relative to breathing He should be the square root of that ratio, which is a change of about 1.2%. For someone with absolute pitch, it may be possible to hear the difference of tone of a musical instrument. But I doubt anyone will hear a difference when a person speaks.

Actually, it would be able to form diatomic molecules, so the mass ratio would be 8.2/4. Taking the square root of that would leave you with a pitch approximately half an octave lower than normal helium.that said, the half-life of this stuff is shorter than the period of many audible sounds, so it's a rather pointless calculation.

Is theorized to work with fusible fuels (say deuterium). But muons don't seem to live long enough to make it practical, they take a lot of energy per to make and have very short lives. In essence, they don't live long enough to catalyze enough fusion to pay back the energy of creation at this point.

So what's interesting is that they were able to do this at all -- either they found a way to extend muon life (unlikely, or that would be the main news here), or they worked insanely fast to get their results before the decay.

In essence, they don't live long enough to catalyze enough fusion to pay back the energy of creation at this point.
That is for free myons!!! As soon as they are bound to an atom core and involved in a chemical bound they live as long as any other particle... e.g. an electron.
Angel

I was unaware of that, can you point me at any paper or research that shows this?
I'd guess that if true, no one noticed as the unbound lifetime is far too short to get one bound by the time you slow it down enough.

I miss the olden days when scientists would speak appropriately about their topics. These days it's too much filmreel, not enough plain real. Too much Hollywood and MTV and too little importance behind their work.

This discovery might really be ground-breaking if it can reduce the volatility of hydrogen and make it more suitable for use in traditional, internal combustion engines in cars and small trucks. I don't believe electric cars are really the answer to a cleaner environment because batteries have a finite life span and use caustic chemicals. However, I believe some scientists expressed concern over helium depletion. Here is a link about a http://www.physorg.com/news201853523.html [slashdot.org]">theory of helium deplet

If it is a theory, it is supported by many strands of scientific evidence, and so should be taken seriously. But maybe it is not a theory, just a hypothesis. Please try not to misuse the word "theory", it only helps the creationists, quack doctors, climate change denialists and so on in their attempts to discredit science.

Government: uhm....Yea..but is it green?
Prof: This is science, applications come after
Government: Can't use it in election. Grant Denied
Next Man: This is high gloss lipstick
Government: Does it help me in Election
Next Man: It will Make PM look 10 years younger with better lips than Angelina Jolie
Prime Minister: Grant for $10,000,0000 approved. Have it ready in 6 months
Ugh!!! could've done better:( I am comedically challenged...

Fleming's team shot muons produced at the TRIUMF accelerator in Vancouver into a cloud of helium, molecular hydrogen and ammonia. The helium atoms captured the muons, then pulled hydrogen atoms away from the molecular hydrogen and bonded with them.

This was all done at TRIUMF, the world's largest cyclotron and by far the best particle accelerator in Canada. Plus, Donald Truhlar (a giant in the field) supported the experimental rate constants with quantum mechanical predictions - very neat stuff indeed!

Good job by our friends to the North, I say -- Props, guys. Denigrating their equipment is ignorant, do you think it takes a better or worse scientist to get to meaningful results on the new shiny stuff, or the older stuff, anyway. Did someone with fancier stuff find this first elsewhere? Then who's got the good scientists, again?

The summary says they start with a helium atom (which has 2 protons and 2 neutrons), and they make it look like a hydrogen atom (with only one proton and no neutrons) my making it *heavier*? This makes no sense whatsoever

I read it too quickly. I'm the one who had it backwards. I thought, because of the muon's negative charge, it would continue to behave like Helium chemically, but would be heavier (presumably like Hydrogen, which is lighter, which is why I thought it was backwards).

They took the Helium atom and replaced one electron with a muon. The clever part is that they managed to get the muon in an orbital shell so low that it effectively cancelled out the positive charge of one of the protons on the nucleus. So it results in an atom with a nucleus of 4 nucleons and one muon (in low orbit) with +1 charge and one electron (in normal orbit) with -1 charge.

Helium is much larger than Hydrogen. Would the bond angles be the same? Would the physical shape of the Helium atom allow it to attach to carbon chains and hexane/benzene structures to make pseudo-hydrocarbons?

By the way... I think the commentator in the attached perspective (http://www.sciencemag.org/content/331/6016/411.full) gets the born-oppenheimer approximation wrong... he states that:

"The BO approximation makes possible the practical application of quantum mechanics to all of molecular science. As the arrangement of the nuclei changes, the BO approximation postulates that the electrons will remain in a particular quantum state. "

When the BO approximation is the opposite : The atoms DONT move while the e

Helium behaves as it does (as an inert gas) because its outer shell is filled. The Pauli exclusion principle means that you can't force another electron into the same place, so an He+ ion would have its extra electron in a higher energy level and very loosely attached. But the Pauli exclusion principle doesn't apply if you have one electron and one muon; the muon's average position is much closer to the nucleus (since the muon is about 200 times heavier), shielding the positive charge of the nucleus. So to

Wow. For the first time I'm actually a little bit freaked out by a science story. They're disassembling an atom and making it behave like a different kind of atom? That's spooky. Here's why this spooks me: This strongly reminds me of the fictional substance "ice-nine" in Vonnegut's Cat's Cradle, which was just a slightly "modified" form of water that was solid at room temperature. It had the unfortunate attribute that it would change any normal water into ice-nine on contact, thus causing a worldwide catacl

Wow. For the first time I'm actually a little bit freaked out by a science story. They're disassembling an atom and making it behave like a different kind of atom? That's spooky. Here's why this spooks me: This strongly reminds me of the fictional substance "ice-nine" in Vonnegut's Cat's Cradle, which was just a slightly "modified" form of water that was solid at room temperature. It had the unfortunate attribute that it would change any normal water into ice-nine on contact, thus causing a worldwide cataclysm when released into the wild. Until this moment I was unable to really picture how one could "modify" a simple molecule like H2O and wind up with something that was still H2O and thus still be able to call it "water". This technique would make that possible.

I hope and pray (to the mythical God that I don't even believe in) that these people messing with the basic structure of atoms know what they're doing. I've never put any stock in silly ideas like the LHC creating black holes or any of that other nonsense people come up with, but this particular story gives me the willies. Helium is one step away from hydrogen. What if they did something similar to a hydrogen atom and it turned out to be able to create new copies of itself just by somehow interacting with normal hydrogen molecules? To those who would immediately say "pish tosh" without thinking about the implications, I'd have to respond by asking how do we know such a thing can't happen when we go around mucking with the very nature of an atom's structure? It's one thing to go around breaking down molecules into their component atoms, or atoms into their component sub-atomic particles, but I think it may be a whole different ball game to go around creating hybrid atoms (and thus hybrid elements) with possibly unknown or unknowable interactions with other atoms/elements.

Or maybe I'm being silly and the scientists know exactly what they're doing. Riiiiiight...

I'll be even more spooked if I find out this sort of thing can't happen in nature. If they're managing to artificially create something that has never been able to exist in the entire history of the universe, it may be time to pull a Peter Griffin, i.e., "WHOA, WHOA, whoa, whoa, whoa, whoa, whooaaa... Are you sure your math is right and you're not gonna destroy the universe?"

Scientists: "Yes."

Peter: "OK. Nevermind."

Scientists: "Whoops!"

Universe: "BOOOOM!!!"

P.S. The new Slashdot is broken. Good job guys. I tried to post this comment once already and it never showed up, but it's listed in the sidebar of my comment page and it wouldn't let me repost the same comment. Even though the link doesn't exist.

I.e. would this become water? I fear producing enough to actually test this theory might be difficult and expensive, but maybe someone knows the theoretical side (not just guessing, I can do that, myself).

Metaphors and anthropomorphization are useful tools for teaching and understanding. Nobody actually thinks that hydrogen is intelligent: the only people who are bothered by this are folks with Asperger's and people with zero sense of humor or creativity. Which are you?

I don't think in the second article that Adam Haslett brought much to the party. He seems to forget that one must first weed the flower bed before cultivating bonsai plants.

Many people have this view of human language akin to believing that your statement grammar is your entire language, which might border on the truth in Forth, Lisp, or APL. Hideously far from the truth if the language contains strong types, OOP, templates, exceptions, closures, or introspecti